Apparatus and method for making mineral wool



March 7, 1939. w, R sElGLE ET AL 2,150,040

APPARATUS AND METHOD FOR MAKING MINERAL WOOL Filed Deo. 26, 1935 INVENTORS. WILL/AM R. SE/GLE. BAILEY TOWNSHEND.

ATTORNEY.

BYE?.

Patented .Man 7, 1939 APPARATUS AND METHOD FOR MAKING MINERAL WOOL William R. Seigle, Mamaroneck, N. Y., and Bailey Townshend,

Westfield, N. J.,

assignors Johns-Manville Corporation, New York, N. Y., a corporation of New York Application December 26, 1935, Serial No. 56,218

7 Claims.

'Ihis invention relates to a mineral wool product and the apparatus and method for making the same.

In the manufacture of mineral wool, it is conventional to provide a suitable slag, rock or other composition in molten condition and to form the molten material into fibres, by allowing the molten material, in the form of a small stream, to fall into a high speed stream of steam. The result is a suspension of the bres in a gaseous medium that is largely air. This suspension is received in a settling chamber. The iibres are there allowed to settle as, for instance, onto a. conveyor screen closing the bottom of the chamber and moving slowly in direction away from the end of the chamber into which the suspension is rst introduced.

An objection to this operation and the product resulting therefrom is the fact that granular or incompletely fiberized material, known as shot, settles along with the libres. Furthermore, the fibres, while still suspended, agglomerate to a large extent into clusters that are inherently Weak and that become bonded in the nished felt, chiefly over the exterior only of the weak clusters.' The result is a non-uniform poorly coherent felt.

It is an object of the present invention to form a more uniform and coherent felt of mineral Wool fibres than previously made from a chemically comparable composition. Another object is to form a felt comprising mineral Wool fibres predominantly oriented in direction generally parallel to the face of the felt and individually felted. Other objects and advantages will appear from the detailed description that follows.

'I'he invention comprises the novel features of apparatus, method and product hereinafter described or illustrated and, particularly, the means and method for and product resulting from felting mineral wool fibres suspended predominantly in individualized, spaced relationship to each other upon a gas-permeable felting member, such as a screen, provided with suction means disposed therebehind.

The invention is illustrated in the attached drawing and will be described in connection therewith.

Fig. 1 is a side elevational view, partly broken away for clearness of illustration and partly diagrammatic, of a preferred embodiment of the invention.

Fig. 2 is a perspective view of our improved product.

u There are shown means indicated generally at II for forming iibres of mineral wool from a suitable molten material and suspending the bres in a gaseous medium Within the chamber I2.

The chamber I2 may be approximately circular 5 in cross section and may extend for a substantial distance in a generally horizontal direction, as, for example, at the illustrated slight inclination upward, in direction away from the position of forming of the fibres.V

Exposed to the suspension in the chamber, say, extending across the chamber or a portion thereof, at the end remote from the position of forming of the iibres, is the gas-permeable felting member I3, such as a screen suitably supported 15 and driven over sprockets I4, I5, and I6. The chamber I2 serves as a conduit to conduct iibres from the iiberizing means to the felting means.

Disposed behind the member I3 are means, such as a funnel-shaped vent I1 connected to a 20 suction fan (not shown) for drawing the gaseous suspension of the fibres through the chamber, forming a felt of the libres upon the member I3 and exhausting, through the resulting felt, gas from the said suspension.

Under the iniiuence of the strong suction used, say, equal to 5 inches of water in vent I'I, the dilute suspension of the fibres in a very large volume of gas is drawn at high speed and in a generally horizontal direction, preferably in sub- 30 stantially non-sinuous manner, through the chamber in direction towards the felting member I3. The fibres remain predominantly in individualized spaced relationship to each other. They are caused to strike the felting member before they become associated to an important extent into large Weak clusters and are caused thus to be individually interlocked (seated) in the felt. Under the inuence of the suction and of bres subsequently deposited, individual libres, once they are seated, are caused to lie predominantly in direction generally parallel to the plane of the face of the felt. The result is a relatively smooth textured, coherent felt having the fibres extending chiefly transversely to the direction of heat flow from face to back of the felt when used as thermal insulation.

While the individualized buoyant bres in suspension are being drawn rapidly through the chamber to the right, there is settling of uniiberized particles, such as the shot", mentioned above, as well as of some brous clusters that may have been formed in spite of precautions to the contrary. Such material may be removed from the system by means of a door 29.

To improve separation of the suspended fibres from settled material, the component of veloc ity of the suspension in a horizontal direction,

should be greater than the component of velocity downward, this downward velocity being due primarily to the force of gravity or to turbulence of the gas suspension.

To minimize, further, settlement of desired fibrous material while permitting the settling out of the shot and heavier materials, there may be admitted a stream or a plurality of streams of secondary or washing gas, as through the ports I8 disposed adjacent to the'bottom of the chamber I2. The gas, such as air drawn through these entrances, under the influence of the suction applied through the means Il, passes inwardlyrand somewhat upwardly against the stream ofjmaterial settling in the chamber, thus buoyi g up the light fibres while permitting settling/olf the heavier materials. The effect is washing away, from settling material, of fibres that may be dislodged easily, with consequent increase in amount of the total fberized material that is obtained in the form of a felt without recycling. Thus the only material collecting on the felting member is the light, fibrous material comparatively free of the less desirable portions formed during the fiberization of the molten mineral material.

The felting member I3 may be moved at a selected speed.' Other conditions being equal, the slower the speed of movement of the said member across the end of the chamber the thicker is the felt formed. We prefer to move the member slowly across the chamber and to form a felt of thickness of the order, say, of a quar-A ter to one inch.

Felts so formed may be plied together to give a composite product of any thickness desired. Thus, the felt may be removed from the felting member or screen, as at position I9, and wrapped upon itself, as around the rotated mandrel 20. The mandrel in turn may be pivotally supported at 2I by means of a bracket 22 that extends downwardly in direction somewhat away from the vertical, so that gravity holds the mandrel lightly against the felt that is being wound spirally therearound.

A light coating of an adhesive, such as a solution of prevulcanized rubber, latex, an oxidizing oil, a resin, and/or asphalt may be applied in a suitable manner, as by spraying at position 23. The adhesive, if used in this manner, forms a thin superficial coating over the felt and adheres together the several plies in the composited product, as illustrated at 24, Fig. 2.

Forlmost purposes, it is desirable to provide thoroughly incorporated binder in small proportion, as, for, for example, by spraying a limited amount of an asphaltic, rubber, oxidizing oil, resin or other conventional binding material into the suspension of fibres near the position of the formation of the said fibres. Thus, a solution of the selected binder in a volatile solvent may be allowed to fall as a small stream into the steam jet at I I, preferably prior to impingement against the molten stream.

While various spacings, arrangements, and dimensions may be used, the distance between the position of initial forming of the fibres, as at II, and that of felting upon the gas-permeable member I3 should be much greater, as measured in a horizontal direction, than the distance of the position II, of formation of the fibres above the bottom of the chamber I2. In other words, the difference in level between position II and the lowermost position of exposure of the felting member in the chamber is very small, so that the fibres that strike the felting'member are moving predominantly lunder the influence of the suction rather than settling under the influence of gravity. 'I'he result is alclassiflcation or separation of the individualized fibres from the undesired heavy particles or aggregations that collect on the bottom of the chamber, the felted fibres being moved continuously away from the bottom of the chamber. We have used to advantage such an inclination of the felting screen that it extendsl approximately vertically and approximately at a right angle to the general direction of movement of the suspension through the chamber, particularly at the end of the chamber,

that is, at the position immediately preceding the felting zone.

The inclination of the screen is adjustable, as by the setting of the supporting arm with respect t0 the frame member 26.

As sealing means for minimizing the entrance of air between the top of the chamber and the felt moving thereby, theremay be used the roller 21, This roller may be forced lightly against the felt, as by the weight 28, so that the roller exerts a gentle smoothing effect upon the felt. Although air is substantially excluded from entering between the top of the chamber and the felt, it is not prevented from entering between the bottom of the chamber and the felting member. Air which so enters at the bottom of the chamber serves to buoy up the light fibres while permitting separation of the heavier particles.

A door provides access to the interior of the chamber for inspection and occasional cleaning.

The binders that are preferred for introduction at position II are soft when warm and adapted to be hardened on cooling, as is the case with such binders as the asphalt that has been mentioned and the common resins, such as rosin. When such binders are used, then the large volume of air drawn through the chamber by the suction causes quick cooling and setting of the binder as well as the production of a felt that may be handled directly after removal from the chamber. On the other hand, excellent results have also been obtained with binders requiring some additional heat treatment such as rubber, oxidizing oils, and convertible resins. An oxidizing (drying oil) such, for example, as linseed and perilla oil, functions especially well in this process, possibly because of the thorough aeration to which the felt is subjected on the felting screen. We have used to advantage about 2 to 4 parts of boiled linseed oil to 100 parts of the rock wool.

It will be understood that the details given are for the purpose of illustration, not restriction, and that variations within the spirit of the invention are intended to be included Within the scope of the appended claims.

What we claim is:

1. In an apparatus for forming and felting mineral wool fibres, means for converting asuitable molten material into fibres and suspending the fibres in a gaseous medium, a generally horizontally extendng chamber positioned to receive the resulting suspension, a gas-permeable conveyor member exposed in the said chamber at the end thereof remote from the position of shredding the molten material, means for felting fibres from the suspension upon the said member and drawing therethroughgas from the said suspension, and means for admitting additional gas through the lower portion of the said chamber to provide gaswashing of ilbrous material tending to settle in the said chamber.

2. In making a felt of mineral wool ilbres, the method which comprises forming a suspension of the ilbres in a gas', drawing the suspension substantially horizontally and at a relatively high velocity through a substantially horizontally extending chamber, drawing additional gas into the said chamber at the lower portion thereof so as to provide gas-washing oi material settling in the chamber, forming a mixture of the said additional gas with the said suspension, and felting the bres from the said mixture on a gas-permeable felting member.

3. An apparatus for producing mineral wool, comprising means for forming bres from heat liquiiied raw material and for suspending the bres in a moving gaseous stream, a chamber for conning and directing the moving stream, openings in the sides of the chamber. for admitting additional gas to promote suspension oi' the libres. and a Ioraminous felting member disposed transversely of the direction of movement of the stream oi! suspended bres.

4. An apparatus for producing mineral wool comprising means for forming ilbres from heat liquitled raw material and for suspending the bres in a moving gaseous stream, a chamber for confining and directing the moving stream, openings in the bottom o! the chamber for admitting additional gas to promote suspension of the bres, and a foraminous felting member disposed transversely oi' the direction of movement of the stream oi suspended ilbres.

5. An apparatus for producing mineral wool comprising means for forming iibres and unberized particles from heat liquied raw material and for suspending the libres and said particles in a moving gaseous stream,r an elongated chamber for conilning and directing the moving stream, the vertical and longitudinal dimensions of said chamber being of suillcient magnitude to enable the particles to settle away from the more buoyant iibres, means for supplying additional gas to said chamber in a direction to separate bres from the settling solid particles, and a ioraminous felting member disposed transversely of the direction of movement of said stream.

6. An apparatus for producing mineral wool comprising means for forming ilbres and unberized particles from heat liquiiled raw material and for suspending the iibres and said particles in a moving gaseous stream, an elongated chamber for confining and directing the moving stream, the vertical and longitudinal dimensions oi said chamber being of sufllcient magnitude to enable the particles to settle away from the more buoyant iibres, means for supplying additional gas to said chamber in a direction to separate iibres from the settling particles, a foraminous ielting member disposed transversely of the direction of movement of said stream, and means for drawinggas from the suspension through said foraminous member and causing felting of bres thereupon.

7. The method of producing mineral wool comprising forming discrete abres and unnberized WILLIAM R. SEIGLE. BAILEY TOWNSHEND. 

